LOS ANGELES (AFP) - Argentina's Juan Monaco ousted second-seeded Benoit Paire of France 6-3, 7-5 on Wednesday to reach the quarter-finals of the ATP clay-court tennis tournament in Houston.

Monaco, the 2012 champion in Houston, notched a second straight tour-level win for the first time since Nice 13 months ago.

He saved 10 of 12 break points he faced and improved to 3-1 against Paire, the world No. 22.

The 32-year-old Monaco booked a quarter-final clash with fifth-seeded American Sam Querrey, a 6-3, 6-3 winner over Germany's Benjamin Becker.

Querrey belted 13 aces and saved the only two break points he faced to overcome Becker in just 50 minutes.

Querrey faces a tough match-up against Monaco - he has never beaten the Argentinian in three prior meetings on clay.

Top-seeded American John Isner advanced on cue, defeating American Denis Kudla 7-6 (7-2), 7-6 (7-4).

Isner next faces young South Korean Chung Hyeon, who rallied for a 5-7, 6-2, 6-2 victory over US wild card Tommy Paul.

Defending champion and fourth seed Jack Sock of the United States launches his campaign on Thursday with a second-round match against Australian qualifier Matthew Barton. Third-seeded Feliciano Lopez and seventh-seeded Marcos Baghdatis will also be in action on Thursday.